This invention relates to a windmill with a controller for controlling rotor rpm and more particularly to an improved governor and method of governing.
With the increased emphasis on energy conservation, there is an increased interest in the use of windmills as power sources. Windmills may be used to provide electrical or mechanical energy from wind power by driving either generators or mechanical devices such as pumps or the like. However, the speed of rotation of the windmill is generally directly related to the wind velocity and unless some governing mechanism is provided, the driven element may be damaged due to high wind forces and high rotational speeds. Although it has been proposed to provide a mechanism for governing the speeds, these mechanisms tend to become complicated and also compromise the design of the windmill.
For example, it has been proposed to provide a governing mechanism in which the pitch angle of the blades of the windmill are changed to control rotor speed. Normally, electrical or hydraulic devices have been employed for changing the pitch angles. However, such pitch angle changing devices themselves consume power and thus reduce the effectiveness of the windill. In addition, it has been the previous practice to position the governor on the output side of the windill in proximity to the driven load. Therefore, it is necessary to provide a complicated mechanism for transmitting the signal from the speed sensor to the blade angle changing mechanism. Not only does this complicate the structure, but it compromises the design of the windmill per se.
It is, therefore, a principal object of this invention to provide an improved method and structure for controlling the pitch angle of the blades of a windmill.
It is a further object of this invention to provide an improved and simplified pitch angle adjusting governor for a windmill that can be located directly at the blades.
It is a yet further object of this invention to provide a pitch angle adjusting device that will incorporate hysteresis.
It is a further object of this invention to provide a governing method for the blades of a windmill that permits the blades to be mounted in a tilting or see-saw fashion so as to improve the performance of the windmill and to minimize the likelihood of damage under shifting wind conditions.
In addition to controlling the pitch angle of the blades of a windmill, there are many other instances where governors are employed. However, governors of the type previously proposed for many applications have not been successfully able to incorporate a hysteresis action, which is desirable in many governor type mechanisms.
It is, therefore, a still further object of this invention to provide a governor of an improved construction which will provide a hysteresis effect.